Publication
Title
Increased detection of smear-negative pulmonary tuberculosis by GeneXpert MTB/RIF (R) assay after bleach concentration
Author
Abstract
Objective/background: The GeneXpert MTB/RIF assay (Xpert) was endorsed as the initial diagnostic tool in people suspected of human immunodeficiency virus-associated or drug-resistant tuberculosis (TB). However, information regarding the performance of Xpert for diagnosing smear-negative TB in high burden settings remains limited. We evaluated the diagnostic accuracy of Xpert and the impact of bleach concentration on the performance of Xpert using smear-negative sputum samples from human immunodeficiency virus-negative patients. Methods: One spot and one morning smear-negative sputum samples per patient were examined using Xpert and culture at the Mycobacteriology Research Center of Jimma University, Ethiopia. The sputum culture on both Lowenstein-Jensen and/or Mycobacteria Growth Indicator Tube was the gold-standard. Results: Of 185 smear-negative presumptive pulmonary TB cases, 19 (10.3%) had culture-proven TB. The sensitivity of Xpert on spot and morning sputum was similar (63.2%). Testing two specimens per patient insignificantly increased the sensitivity of Xpert. Bleach concentration and pelleting improved the sensitivity of Xpert over unprocessed sputum in paired samples (73.8% vs. 63.2%) without affecting the specificity (95%). Bleach concentration and pelleting allowed an additional seven cases of TB (missed on the first and second direct Xperts) to be detected, five of which were from culture-negative cases. Conclusion: Testing of a single sputum sample by Xpert can reach reasonable sensitivity and results would be available on the same day, avoiding loss of patients and treatment delay. The sensitivity of Xpert was improved after bleach concentration and pelleting, although its added value needs further study on a larger scale. (C) 2016 Asian-African Society for Mycobacteriology. Production and hosting by Elsevier Ltd. All rights reserved.
Language
English
Source (journal)
International Journal of Mycobacteriology
Publication
2016
ISSN
2212-5531
Volume/pages
5:2(2016), p. 211-218
ISI
000376688000015
Full text (Publisher's DOI)
Full text (open access)
UAntwerpen
Faculty/Department
Research group
Publication type
Subject
Affiliation
Publications with a UAntwerp address
External links
Web of Science
Record
Identification
Creation 05.07.2016
Last edited 09.06.2017
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